This invention relates to a method and apparatus for detecting abnormal conditions or faults of a circuit breaker from outside thereof.
About 90% of the faults of a circuit breaker are mechanical faults such as leakage of air, gas or oil, a fracture and inoperative state or an improper operation of the circuit breaker itself or an operating mechanism thereof. The leakage of air, gas or oil can be detected with a pressure relay for producing an alarm signal whereas an inoperable state or improper operation can not be detected until such faults occur because in most cases, various elements of the circuit breaker do not move but should be moved as desired when a fault occurs on a power circuit.
With recent increases in the demand for power, the operating voltage and capacity of the circuit breaker increases year by year and any fault or abnormal condition thereof results in a serious problem.